Developing Soft Switching in Solid-State Circuit Breakers

This paper aims to apply silicon-carbide (SiC) MOSFETs to solid-state circuit breakers (SSCBs) including active injection circuits (AIRCs) for DC systems. SiC MOSFETs are employed in main and auxiliary circuits to provide a fast response time and compact design. Benefiting from AIRCs, fault current is reduced to zero in the main switch during DC current interruption. The obtained soft-switching helps to mitigate the effects of parasitic components and utilize the fully capabilities of the SiC MOSFETs in SSCBs. To select the optimized values of the passive components in the auxiliary branch, a design procedure is developed. The presented topology is verified using simulations of 4kV/100A in LTspice environment and experiments of a downsized 380V/15A prototype with a response time of 2.8µs.